High-Efficiency Colloidal Quantum Dot Photovoltaics via Robust Self-Assembled Monolayers

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• 作者：Gi-Hwan Kim ; F. Pelayo Garc铆a de Arquer ; Yung Jin Yoon ; Xinzheng Lan ; Mengxia Liu ; Oleksandr Voznyy ; Zhenyu Yang ; Fengjia Fan ; Alexander H. Ip ; Pongsakorn Kanjanaboos ; Sjoerd Hoogland ; Jin Young Kim ; Edward H. Sargent
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：November 11, 2015
• 年：2015
• 卷：15
• 期：11
• 页码：7691-7696
• 全文大小：423K
• ISSN：1530-6992

文摘

The optoelectronic tunability offered by colloidal quantum dots (CQDs) is attractive for photovoltaic applications but demands proper band alignment at electrodes for efficient charge extraction at minimal cost to voltage. With this goal in mind, self-assembled monolayers (SAMs) can be used to modify interface energy levels locally. However, to be effective SAMs must be made robust to treatment using the various solvents and ligands required for to fabricate high quality CQD solids. We report robust self-assembled monolayers (R-SAMs) that enable us to increase the efficiency of CQD photovoltaics. Only by developing a process for secure anchoring of aromatic SAMs, aided by deposition of the SAMs in a water-free deposition environment, were we able to provide an interface modification that was robust against the ensuing chemical treatments needed in the fabrication of CQD solids. The energy alignment at the rectifying interface was tailored by tuning the R-SAM for optimal alignment relative to the CQD quantum-confined electron energy levels. This resulted in a CQD PV record power conversion efficiency (PCE) of 10.7% with enhanced reproducibility relative to controls.